Fusion energy: is the breakthrough finally imminent?

“In 30 years” – that was the joke about fusion energy for decades. But something has happened in the last few years.

What fusion promises

It fuses atomic nuclei instead of splitting them - like the sun. The result: enormous amounts of energy, hardly any long-lived waste, and no risk of a core meltdown. A single gram of fuel can theoretically provide as much energy as several tons of coal.

The fuel comes from hydrogen variants that can be obtained from water and rock - so it is available in virtually unlimited quantities. Unlike nuclear fission, no highly radioactive waste is created that has to be stored for thousands of years.

Why there is movement now

• Stronger magnets: New superconductors make more compact reactors possible.
• Private capital: Billions are flowing into dozens of start-ups.
• Net energy gain: Initial experiments generated more energy than they consumed.

The last point in particular was a historic moment. For decades, researchers put more energy into the systems than was ultimately produced. The fact that this point has been exceeded has electrified the industry and attracted new money.

Fusion does not solve today's climate crisis - but it could become the energy source of the next century.

The big hurdles

But the road to becoming a power plant is long. Showing an energy gain in the laboratory is one thing, repeating it permanently, reliably and economically is quite another. The materials must withstand extreme heat and radiation for years, and the systems must provide electricity that can compete with solar and wind power.

Why not just wait?

Some ask: If fusion is so far away, why all the money? The answer lies in the size of the promise. A 24/7 energy source that uses almost no fuel and leaves little waste would not only replace power plants, but enable things that are too energy-hungry today - from large-scale desalination of seawater to the production of clean fuels.

At the same time, competition drives all of science. Even if not every start-up is successful, better magnets, materials and controls are created that are also useful elsewhere. Research of this kind often pays off in ways no one foresaw.

The Honest Time Horizon

Commercial power plants remain a good decade away, perhaps longer. Anyone who sells fusion as a solution for the next ten years is exaggerating. But for the first time, engineers are talking about when, not if. And it is precisely this shift – from dream to engineering task – that is the real news. Sun, wind and storage remain the mainstays of climate protection in the coming years; they are available and cheap. Fusion is not a replacement for it, but rather a possible addition for the second half of the century. If you classify both soberly, you avoid both excessive euphoria and hasty resignation.